Structure of amorphous germanium and silicon

摘要

Amorphous vapour-deposited films of germanium and silicon have been examined by means of Cu Ka, MoKa and filtered Ag radiation. The interfering K radiation from germanium was eliminated by means of a silver or palladium foil of thickness 100 or 150 p.. Fourier analysis of the intensity curves gave practically identical atomic distribution curves for all types of radiation. It follows that amorphous germanium and silicon have a layer group structure of (111) planes with thickness about 15 A- The layers are heavily perturbed, even individually. Layer formation appears to be a general and important feature of the amorphous non-crystalline state. Because of the requirement of continuous space-filling, the groups are joined by transition regions in which the atoms have a largely disordered distribution.